1. Field of the Invention
This invention relates to a lined multi-branch fitting and method of making a lined multi-branch fitting having a plurality of individual metal housing members which are assembled over a one-piece, multi-branch, heat degradable liner and more particularly to a lined multi-branch fitting having confronting metal housing members which are welded together with a fillet weld and include an insulating projection on one of the housing members received in a complementally formed recess in the other of the housing members for insulating the liner from weld heat applied to the other housing member.
2. Description of the Prior Art and Objects
A lined multi-branch fitting constructed according to the present invention is particularly adapted for use in coupling metal pipes lined with plastic or glass such as that utilized in the transporting chemicals in the chemical transport industry. The fittings constructed according to the present invention couple elongate runs of piping to transversely disposed fluid distribution lines or laterals which extend off a main run. Such fittings typically are T-shaped fittings although it should be understood that the neck or stack on such fittings can extend at an angle other than 90xc2x0 to the main run. One such fitting has a T-shaped liner that is molded into a T-shaped metal fitting, but this fitting is expensive and the process of manufacture is time consuming.
Also, relevant to an understanding of the invention is an understanding of the limitations imposed by the types of welds that might be incorporated in coupling adjacent pipe sections together.
One prior art method of coupling lined pipe sections included abutting adjacent ends of pipe sections to be coupled and then xe2x80x9cbutt-weldingxe2x80x9d the abutting adjacent ends together. Although such welds are very strong, such welds are relatively more expensive than a fillet weld. Firstly, building and construction codes commonly require that the weld metal in butt welds extend completely through the abutting ends and thus, substantially more time and weld metal is required than is required in a fillet weld. In addition, butt welds must typically be x-rayed and spot checked for quality and such x-raying is expensive. Finally, the butt welding technique requires higher skill than that required for a fillet weld. Accordingly, it is an object of the present invention to provide a multi-branch lined fitting which includes adjacent metal housing parts that are coupled together with fillet welds as opposed to butt welds.
When welding two pieces of metal together, it has been found advantageous to apply more heat to one of the parts than to the other. The problem attendant to doing this, however, is that more heat will be transmitted to the lining by the part having more heat supplied thereto. Accordingly, it is another object of the present invention to reduce the transfer of weld heat transmitted to the adjacent portion of the heat degradable lining disposed therein.
It is further object of the present invention to provide a multi-branch lined fitting of the type described which includes a barrier to inhibit burning of the heat degradable liner disposed in the fitting.
It has been found, according to the present invention, that inserting an insulator between an external portion of one of the housing parts and an interior lining is advantageous in preventing heat degradation of the lined material. Accordingly, it is an object of the present invention to provide a lined multi-branch fitting of the type described including an insulator which is disposed adjacent the interior portion of one of the fitting parts and the exterior portion thereof.
It has been found according to the present invention, that an adequate insulator can comprise a female slot on the radially inner portion of the part to which the primary weld heat is to be applied and a male projection on the other metal housing member to be connected thereto which is received by the slot. Accordingly, it is another object of the present invention to provide a multi-branch lined fitting of the type described wherein an insulator is integrally provided on one of the metal housing members for being received in a complementally formed notch in the other housing member.
It is another object of the present invention to provide a lined multi-branch fitting of the type described wherein the metal housing member, including the male insulating projection, comprises a groove in a radially outer portion thereof for receiving weld metal for forming a fillet weld bead to couple the metal housing parts together.
It is another object of the present invention to provide a multi-branch fitting of the type described which couples two metal sections, each having a hollow cylinder and a transversely disposed substantially semi-cylindrical metal half stack mating with the other half stack to form a cylindrical stack transverse to the hollow cylinder, with a new and novel insulating fillet welded joint therebetween.
It is another object of the present invention to provide a multi-branch lined fitting of the type described including a metal housing comprised of two axially aligned hollow cylinders and a transversely disposed metal cylindrical stack with the stacks having confronting terminal ends welded together via a fillet weld.
It is a further object of the present invention to provide a T-type fitting of the type described including a heat insulator comprising radially inner cooperating male and female parts at the junction of the metal housing members.
The following patents, although not disclosing or remotely suggesting the concepts, structure and method disclosed and claimed herein, were selected during a preliminary patentability search, and are cited as being of interest:
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.
A multi-branch fitting comprising: a one-piece multi-branch hollow liner having a plurality of individual confronting metal housing members assembled over the liner and disposed in confronting relation with each other; and a fillet weld bead integrally coupling the terminal ends of confronting mental housing members together. The invention also contemplates the method of fabricating a multi-branch fitting which includes the step of utilizing an elongate insulating tongue on a radially inner terminal end of one of the housing members for insulating a portion of the liner radially adjacent a radially inner slotted portion of the other metal housing members from weld heat applied to a radially outer portion of the other housing member.